<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_变量与常量</title>
</head>
<body>
<script>
    var a = 1;
    console.log(a);
    var b = 3.14;
    console.log(b);
    var c = true;
    c = false;
    c = 'ahhh'
    console.log(c);
    var c = "aiheihei"
    console.log(c);
    // d = "直接定义变量,造成全局作用域污染"
    // console.log(d);
    let x = 1;
    console.log(x);
    let x = 666;
    console.log(x);

    const y = 1;
    console.log(y);
    // y=2;常量的值不让改
</script>
</body>
</html>